I ordered a all grain kit from brewmasters. http://www.brewmasterswarehouse.com/recipe/d66b18b3/ The kit was for making 5 gallons. The instructions call for 3.5-4 gallons for Mashing @ 80 minutes. Then 4.5-5 gallons for spargeing. Then boiling for 60 minutes while hopping. I did this on a stove top. I used a lid throughout the process. When i was done i had 7 gallons to ferment. I had to add about a cup of sugar to get the SG up. After fermentation the beer is watery. Was i suppose to leave the lid off the hole time? I though it was kinda odd that for a 5 gallon batch i end up with 7. Thanks for any help you can offer. I reordered the kit for another try.

Another thing to think about - the instructions that came with your kit pertain to a certain setup. You may not have needed all that water due to mash tun geometry, heat, grain temps, humidity, planet alignment etc.

Another thing to think about - the instructions that came with your kit pertain to a certain setup. You may not have needed all that water due to mash tun geometry, heat, grain temps, humidity, planet alignment etc.

Yeah, i read somewhere that it's better to use less water before you know your efficiency. Cause one can always add more water. Thanks for the reply.

Having the lid on kept all the steam in. No steam out=no boil off=7 gallons instead of 5.

Not totally true. Unless you have a pressure cooker that you boil your beer in, you will still have evaporation. Regular pots aren't a sealed environment, so they will still let some steam out.

The reason you don't boil with a lid on is because during the boil you produce DMS. Normally, this evaporates and floats off into the ether. If you leave the lid on, the steam (containing some DMS) condenses onto the cooler surface and then drips back into the wort. Not what you want.

If you straight up followed the directions, that's where you went wrong unfortunately. It seems like it calls for around 8 gallons total, which would make sense since you boiled for an hour and got 7 gallons. In the future, you want to measure your first runnings from your mash and subtract that from your desired preboil volume. That is the amount that you want to sparge with and if you do it this way you will always get the amount of wort that you need to boil down.

Always heat up more water than you think you will need, but you don't have to use it necessarily.

You can measure your boil off rate, just measure the volume of liquid at the start of the boil, then again after 60 min, with the lid off. I usually get about 0.5 gal/hour on my electric stove on the highest setting, but if you're outside, using a propane burner, you may get 1 gal/hour or more. Then do what devilishprune said and only sparge with enough water to get to your preboil volume.